Cool, Wet and Briefly White: October 2009 Overview

Dr. David A. RobinsonNew Jersey State ClimatologistCenter for Environmental Prediction, School of Environmental and Biological
Sciences/NJAES, Rutgers UniversityNovember 5, 2009

Being a transition month, some October days provide lingering summer warmth, while others may bring early reminders of the winter ahead. Stretches of dry weather may prevail, as summer thunderstorms diminish while winter low pressure systems have yet to place New Jersey in their sights. However either of those wet occurrences may arise, or even a late tropical system. While NJ didn't see a tropical visitor this past October, all of the other conditions were in evidence, including a very windy day more often seen in the spring than in fall.

Prior to examining the stormy side of the ledger, let's first look at the thermometer. The 53.6° statewide average temperature was 0.6° below normal. This is tied with three other years as the 40th coolest of the past 115 Octobers. Warm and cold episodes alternated throughout the month. Low temperatures reached 32° at Pequest (Warren County) and Berkeley Township (Ocean) on the 2nd, but warmed quickly to highs of 78° on the 3rd at Sicklerville (Camden) and Upper Deerfield (Cumberland), and the 4th at New Brunswick (Middlesex), Chatham (Morris) and Berkeley Township. Woodstown (Salem) and Sicklerville reached 80° on the 9th for the warmest temperature of the month. Highs reached 76° at these two locations as well as at Woodbine (Cape May) and Sea Girt (Monmouth) on the 10th, preceding the arrival of more cold air on the 11th (31° at three locations) and 12th (27° at Walpack (Sussex)). A rather widespread freeze visited the state on the 14th, with Walpack falling to 26° and temperatures at or below freezing in eight counties. An exceedingly cool mid-October day followed on the 15th, with High Point (Sussex) only climbing to 36°, Wantage (Sussex) to 38° and Atlantic City Marina (Atlantic) being the "warm" spot at 54°. Several locations had lows in the upper 20s to low 30s on the 15th, 16th and 18th. The coldest morning of the month occurred on the 19th, with a low of 24° at Walpack and almost every station outside of urban areas or along the coast dipping below freezing. Atlantic City Mariana was again the "warm" spot with a low of 46°, while the next mildest location was Harvey Cedars (Ocean) at 39°.

The 20th brought another subfreezing morning to a number of locations, but warmth quickly followed. Chatham and Sicklerville climbed to 76° on the 21st and Chatham (79°), Haworth (78°) and Walpack (78°) were the warm spots in north Jersey on the 22nd. A few colder spots dipped below freezing on the 26th and 27th, with the month finishing on the warm side, especially in the southern half of the state where the Halloween high was 76° at Berkeley Township. Walpack took top honors with eight subfreezing minimums in October, while at month's end, coastal and urban areas have yet to see a freeze.

October statewide average precipitation preliminarily stands at 5.67". This is 2.16" above normal, making this the 16th wettest since 1895. The southern half of the NJ was a bit wetter (5.68") than the north (5.35"), making for a more equitable balance than September's wet south and dry north. Southern coastal counties took top honors, with Linwood (Atlantic) and Woodbine (Cape May) CoCoRaHS stations reporting 8.61". Another Woodbine station caught 8.18", which was also the total in nearby Upper Township (Cape May). Six to eight inches fell in ten counties, including from south to north, Cape May, Atlantic, Ocean, Burlington, Monmouth, Mercer, Hunterdon, Morris, Passaic and Bergen.

Drier conditions prevailed in portions of southwest and northwest Jersey, though precipitation totals were still an inch or so above average. The only stations with less than 5" for the month included 4.19" at Bridgeton (Cumberland), 4.86" in Franklin Township (Gloucester), 4.27" in Vernon Township (Sussex), 4.56" at Knowlton Township (Warren) and 4.82" in Jefferson Township (Morris).

There were several rainy episodes in the month. An isolated downpour early on the 3rd produced 3.27" at Harvey Cedars and 1.66" at West Creek in coastal Ocean County. An extended dry spell followed and was not broken until the 15th when West Creek caught 1.20". Most noteworthy on that day was the snowfall in portions of the northwest. Higher elevation totals included 4.0" at Vernon, 3.0" at High Point (Sussex) and 2.7" in Wantage, all in Sussex County. In Morris County, Randolph received 2.2" and Roxbury 1.0", while Blairstown (Warren) caught 2.0". While valley locations also saw light accumulations of the white stuff, much of it melted on contact, as suggested in the photo accompanying this piece. Some light snow and sleet fell on the morning of the 16th even to Chatham (Morris) but did not accumulate.

A south Jersey-focused event brought 1.64" to Elk Township and 1.53" to Woolwich Township, both in Gloucester County, on the 17th-18th. The north was the wettest part of the state on the 23rd-24th, with 2.64" in Westfield (Union), 2.63" at Parsippany-Troy Hills (Morris) and 2.61" at Kearny (Hudson). All told, 41 CoCoRaHS reports around the state exceeded 2.00" over those two days. An even wetter event centered on the south on the 27th-28th. 3.64" fell in Sea Isle City, 3.41" in Lower Township and 3.03" in Upper Township, all in Cape May County. 45 CoCoRaHS stations exceeded 2.00" over those days.

While spring months are often windier than those in the fall, October 2009 had its share of windy days. Most notable was a fair-weather wind event on the 7th when winds gusts reached 53 mph at the Atlantic City Marina (Atlantic), 51 mph at Seaside Heights (Ocean) and 50 mph at Woodstown (Salem). Gusts exceeding 40 mph were observed in eight counties, leading to some downed trees and power outages. Seven other days saw gusts exceed 40 mph at one or more Jersey stations at higher elevations or along the coast. The most notable day was the 15th, with a 49 mph gust at Seaside Heights and 46 mph at Harvey Cedars.